1 files changed, 55 insertions, 0 deletions
diff --git a/vb/env.vb b/vb/env.vb
new file mode 100644
index 0000000..3095344
--- /dev/null
+++ b/vb/env.vb
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+Imports System.Collections.Generic
+Imports Mal
+Imports MalVal = Mal.types.MalVal
+Imports MalSymbol = Mal.types.MalSymbol
+Imports MalList = Mal.types.MalList
+
+Namespace Mal
+    Public Class env
+        Public Class Env
+            Dim outer As Env = Nothing
+            Dim data As Dictionary(Of String, MalVal) = New Dictionary(Of String, MalVal)
+
+            Public Sub New(new_outer As Env)
+                outer = new_outer
+            End Sub
+            Public Sub New(new_outer As Env, binds As MalList, exprs As MalList)
+                outer = new_outer
+                For i As Integer = 0 To binds.size()-1
+                    Dim sym As String = DirectCast(binds.nth(i),MalSymbol).getName()
+                    If sym = "&" Then
+                        data(DirectCast(binds.nth(i+1),MalSymbol).getName()) = exprs.slice(i)
+                        Exit For
+                    Else
+                        data(sym) = exprs.nth(i)
+                    End If
+                Next
+            End Sub
+            
+            Public Function find(key As String) As Env
+                If data.ContainsKey(key) Then
+                    return Me
+                Else If outer IsNot Nothing Then
+                    return outer.find(key)
+                Else
+                    return Nothing
+                End If
+            End Function
+
+            Public Function do_get(key As String) As MalVal
+                Dim e As Env = find(key)
+                If e Is Nothing Then
+                    throw New Mal.types.MalException(
+                            "'" & key & "' not found")
+                Else
+                    return e.data(key)
+                End If
+            End Function
+
+            Public Function do_set(key As String, value As MalVal) As Env
+                data(key) = value
+                return Me
+            End Function
+        End Class
+    End Class
+End Namespace